Grate.



G. M. S. TAIT.

GRATB.

APPLICATION FILED 10v. 4, 1912.

Patented Nov. 11,1913.

3mm Mon form,

UNITED STATESFPATENT oFFroE.

GODFREY M. S. TAIT, OF WASHINGTON, DISTRICT GOLUMBIA.

GRATE.

Specification of Letters Patent.

Patented Nov. 11, 1913.

Application filed November 4, 1912. Serial No. 729,482.

To all whom it may concern:

Be it known that I, GODFREY M. S. TAIT, a subject of the King of Great Britain and a resident of Washington, District of Columbia, have invented certain new and useful Improvements in Grates, of which the following is a specification.

My invention relates to improvements in grates for furnaces, gas producers and the like, and comprises a rotatable spirallystepped grate of approximately conical the several steps being so positioned with respect to one another that-the fuel or ash lying upon these steps assumes the natural angle of repose, such fuel or ash being disturbed only by rotation of the grate as a 'whole, the disturbance ceasing when the rotation is stopped. The action of the grate when stationary .is that of a repose grate composed of concentric rings, but when the grate is rotated it cuts 1ts way through the ash and fuel bed, then acting as an anger to remove the ashes, clinkers, etc., such ash and clinkers, etc., then spilling over the edge of the grate inwardly throughout its entire spiral length. In case there are clinkers too large to pass between the steps of the grate, su'ch clinkers will be moved down along the spiral until they reach the bottom ortion of the grate, where, if not then bro (en up, as a result of such mot-ion, they may be removed through a suitable clinker door provided for that purpose.

My invention comprises a grate compris ing a continuous conical spiral body or grate-bar, the several turns or steps of which overlap one another, there being. intervening spaces between the overlapping turns or steps for the escape ofash, clinker and the like; my invention. also comprises a grate such as referred to wherein the several turns or steps are so spaced apart that the fuel I and ash lie upon such steps in natural repose hillocks, escaping through the spaces between the said steps or turns only when the grate is rotated; and my invention further comprises a grate such as above referred to wherein the several turns or steps are by a central strut, and by arms from that strut; my invention further comprises a water-cooled grate construction and other features as hereinafter described and particularly pointed out in the appended claims. V

The objects of my invention are to improve the'construction of grates, particuradiating larly' gas producer grates; to. so construct the rate that there shall be ample spaces for t e flow of air. or gas, and for the escape of ash, clinker and the like, while at the same time there shall be practically no fallmg of the fuel through. the spaces between the steps of the grate, while the rate is stationary; to provide a grate w ich, when moved or shaken, shall discharge the ash efliciehtly, and shall clean the fire thoroughly; to so construct the grate as to counteract the natural tendency for the fuel to burn out more rapidly at the sides of the furnace or roducer than at the center; to provide a simple, sectional construction; to provide for efiicient watercoolin of the grate; and in general to make tie grate simple, efficient, easy to operate and relatively inexpensive.

I will now proceed to describe my invention with reference to the accompanying drawings, and will then point out the novel features in claims.

In the drawings: Figure 1 shows a central vertical section of the lower portion of agas producer provided with a water cooled grate constructed in accordance with in invention. Fig. 2 shows a top view 0 the grate. Fig. 3 is a detail fragmentary top view illustrating the sectional construction of the grate. Fig. 4 is a view similar to Fig. 1, illustrating a grate which is not water cooled. Fig. 5 is a detail fragmentary side view of a plain .or non-watercooled grate, illustrating the manner of connection of the sections. of the grate-step. Fig. 6 is a view similar to Fig. 5 illustrating the connections of the sections of a water-cooled grate. Fig. 7 is a detail sectional view of a water-cooled grate illustrating the construc-' tion where the spiral departs from the lane lower step of the grate. Fig. 8 is a etail vertical section on a plane different from that of Fig. 1, showing the junction of the hollow spiral body 11 with the water ,flange 9 which guards the ball against the entry. of ash therein.

or mast 6is provided with a de nding earing Numerals 10 designate arms projecting radially from the mast or strut 6, and numeral 11 designates a spiral grate bar or body supported by these arms 10, and so by the central mast 6. The lower ring, turn or step of this grate bar is a plane ring, from which the spiral departs at a suitable point, as indicated in Fig. 2, and Fig; 7, such spiral rising conically' and helically until it finally merges into a hollow cap 12, the interior of which is in communication withthe bore 13 of the central mast or strut 6. The said grate bar, in the construction shown in Fig. 1, is hollow, the top turn communicating with the interior of the hollow cap 12, and the bottom turn having a water discharge pipe 14. A water supply pipe 15 enters the hollow base 7 and passes upwardly through the hollow mast 6.

My grate is adapted for use either in updraft producers or furnaces, or in down- ,draft producers or furnaces. water cooling of grates is required only m In general,

7 solid, as indicated in Fig. 4, wherein numeral 11 designates the said spiral body or grate bar. 4

For discharging ash, clinker, etc., I provide means for rotating the grate structure, such means comprising a circular rack 18 on the lower side of the bottom turn of the grate, and a pinion 19 intermeshing with said rack and arranged to be rotated by suitable means, such for example 'as the crank 20.

As shown, the several turns ofthe spiral body of the grate are so spaced apart that the fuel or ash lies upon the several turns or steps of the grate in angle of repose hillocks. The distance between the several turns or steps of the grate, i. e. the pitch of. the grate, will be varied somewhat according to the nature of the fuel and of its ash, diflerent fuels and different'ashes having somewhat different angles of repose, which angles of repose are well known to those skilled in the art. Because the pitch of the grate issuch that fuel and ash lie upon it 1n angle of repose hillocks when the grate is stationary, there .will be no escape of fuel, through the spaces between the turns of the grate while the grate is stationary. But when the grate is rotated in the proper direction by means of the arm 20, the grate bores into the mass of ash, clinker and fuel lying upon it, somewhat after the manner of an auger, discharging the ash through the spaces between the turns of the grate into the central'portion of the ash pit breaking up clinker, and causing the fue to drop down to take the place of'the ash. Rotation of the grate tends to break up any arches that may have formed in the portion of the fuel bed in the immediate vicinity of the grate, thus promoting regular descent of the fuel.

As illustrated particularly in Figs. 3 and 5, the grate, whether of the construction shown in Fig. 4, or of the water cooled construction shown in Fig. 1, comprises a plurality of separable step-sections secured to the arms 10, and also secured to one another; andin the case of the water cooled grate there may be a suitable gasket 21 between each two sections so joined.

Since the grate slopes from the center downwardly and outwardly, the fuel bed is deepest at the sides. In various grates which have been used to some extent, the

reverse vis true, the grate sloping downwardlyand inwardly with the result that the fuel bed is deepest at the center. It has been found in such grates that since the fire tends to burn more rapidly at the sides than in the center, the fuel burns out at the sides before it does at the center, and in shaking or otherwise actuating the grate to shake out the ash, much .incompletel burned fuel comes down with the ash and is wasted. In my construction as shown,

since the fuel bed is deepest at the sides, the fuel will burn out with substantial uniformity throughout the cross section of the producer, and in the rotation of the grate practically all of the ash will be worked out before unburnt fuel from any portion of the fuel bed begins'to come through.

I provide the producer with the usual clinker door 22, the door-way being filled in with fire brick laid in loosely. In case of formation of clinkers too large to pass the grate and too tough to be broken up .by the grate, these clinkers may be worked around by rotation of the grate, until opposite the clinker door-way, and then may be removed through such doorway.

In the water cooled form of grate shown in Figs. 1 and 2, I have indicated the hollow cap 12 as open at the top, for the escape of any vapor which may be formed, and have indicated a protecting cover 23, which prevents entrance of coal or ash into the hollow mast 6.

What I claim is.

1. A grate comprising a conical body consisting of spiral overlapping steps with intervening spaces for the escape of ash into the space surrounded by the grate, such grate being broad at the base and narrow at the top in combination with means for producing'rel'ative rotary motion between such 2. A grate comprising a conical body consisting of spiral overlapping steps with intervening spaces for the escape of ash into the space surrounded by the grate, such grate being broad at the base and narrow at the top, the several steps overlapping one another to an extent corresponding to the angle of. repose of the material to be supported in combination with means for producing relative rotary motion between such grate and material to be supported thereon. 3. A grate comprising a conical body consisting of spiral overlapping steps with intervening spaces for the escape of ash into the space surrounded by the grate, such grate being broad at the base and narrow at the top, and means rotatably supporting said grate.

4. A grate comprising a conical body consisting of spiral overlapping steps with intervening spaces for the escape of ash into the space surrounded by the grate, such grate being broad at the base and narrow at the top, the several steps overlapping one another to an extent corresponding to the angle of repose of the materialto be supported, and means rotatably supporting said grate.

5 A grate comprising a central mast, arms projecting therefrom and a spiral grate-body supported on said arms, and winding from the bottom upward and toward the center, the several turns of such body overlapping one another and separated from one another by spaces forthe escape of ash from the outside of the grate into the space surrounded by the grate.

6. A grate. comprising a hollow conical body consisting of hollow spiral overlapping steps with intervening spaces for the escapeof ash into the space surrounded by the grate, such grate being broad at the base and narrow at the top, in combination with means for producing rotary motion between such grate and material to be supported thereon and means for supplying cooling fluid to said hollow spiral steps.

7. A grate comprising a hollow central mast, a hollow conical body consisting of hollow spiral overlapping steps with intervening space for the escape of ash, surrounding and connected to said mast, the

hollow steps of such conical body connected to the upper portion of such mast, and means for circulating cooling fluid through said hollow. conical body.

8. A grate comprising a hollow central mast, having a tvater chamber at its upper end, a conical grate-body secured to said mast, such conical grate-body comprising a plurality of spiral conical turns overlapping one another to an extent corresponding to the angle of repose of the material to be supported, said body being hollow and connected-at its upper end to the water chamberat the top of said mast, and a Water connection to the lower portion of said body.

9. A grate comprising a hollow central mast, having a water chamber at its upper end, a conical grate-body secured to said mast, said grate body comprising a plurality of spiral conical turns overlapping one another to an extent corresponding tothe angle of repose of the material to be supported,

said body being hollow and connected at its 4 upper end to the water chamber at the top of. said mast, and a water connection to the lower portion of said body, said water chamber being open at the top, and a protecting cap covering said opening of the water chamber, and serving to prevent the entrance of ash or fluid therein.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

I GODFREY M. S. TAIT. Witnesses: I

H. M. MARBLE, F. E.'BARRows. 

